Geochemistry & Geomaterials Research Laboratories (GGRL)

Wet Chemistry Laboratory

The Wet Chemistry Laboratory specializes in the broad-spectrum inorganic analysis of water, gas, and solid samples. Several organic compounds such as water-soluble tracers and high explosives can also be determined. Examples of past and present applications include analysis of fluids for geothermal system exploration; fluid analysis and remote sensing in volcano research; environmental water and soil analysis; and studies involving organic and inorganic tracers in water and solid materials. Central to the laboratory is an Inductively Coupled Plasma (ICP) Atomic Emission Spectrometer and an ICP-Mass Spectrometer fitted with an auxiliary laser ablation sampler. Other instrumentation includes Atomic Absorption, Ion Chromatography (for anions in water, rock fusions, and gas caustics), High-Pressure Liquid Chromatography (organic tracers, high explosives), Gas Chromatography for non-compressible gases; and Total Carbon Analysis for organic and inorganic carbon in liquids and solids.

X-Ray Diffraction Laboratory

X-ray diffraction (XRD) is the preferred method for phase identification as it provides unambiguous solid-phase information. EES-14 has made substantial contributions to quantitative X-ray diffraction methods. The Rietveld quantitative analysis method was pioneered in our laboratory, as were other major enhancements. We also recently developed a new full-pattern quantitative XRD method that is flexible and easy to use, yet produces precise and accurate results. XRD samples can be analyzed at temperatures from liquid N2 to 300 C°, in vacuum or inert-gas atmospheres. Experiments can also be conducted under precisely controlled humidity conditions from 0-100% relative humidity using an EES-developed computer-automated humidity control system.

This system is particularly useful for analysis of hydrous phases such as clay and zeolite minerals. We have used XRD to measure structural changes of minerals during heating and water sorption/desorption, to perform crystallite size/strain measurements, and to detect trace amounts of hazardous minerals (e.g., erionite down to ~250 ppm). We have also used the lab to determine and refine several mineral crystal structures and for the identification of yoshiokaite, a new mineral obtained from the surface of the Moon.

Thermal Analysis

The EES-14 thermal analysis capability consists of a suite of instruments including thermogravimetric analyzers (TGA, which monitors the weight of a sample as a function of a change in temperature and/or atmosphere), a differential scanning calorimeter (DSC, which monitors the heat flow from a sample as a function of temperature and/or atmosphere), and a moisture evolution analyzer (MEA, which measures the water content of a sample). In addition, the laboratory has a full suite of teflon-lined pressure vessels, including Parr vessels, for elevated-pressure experiments. A unique feature of the laboratory is a VG quadruple mass spectrometer that is linked directly to the TGA instrument to determine the composition and abundance of gases evolving while heating a sample.

Optics

The GGRL has an extensive suite of optical equipment including a fluid inclusion heating stage and microscope, a cathodoluminescence microscope, a Fourier-transform infrared spectrometer with conventional and microscope stages, and a complete suite of optical microscopes for analysis of geologic thin sections.

Light Stable Isotope Laboratory

EES-14 has a Micromass IsoPrime Continuous-Flow Isotope Ratio Mass Spectrometer. This instrument is a highly automated, high throughput system that represents the cutting edge in continuous-flow light stable isotope mass spectrometry. With this system, we are able to conduct various measurements on oxygen, carbon, nitrogen, and hydrogen isotopes in waters, carbonates, soils, dissolved inorganic carbon (DIC), bulk organic materials, etc.

This system fills in gaps in our current geochemical capabilities and has already been lined up to assist in studies of carbon sequestration, water cycles, and to support ocean modeling efforts. The instrument can also be used for biogeochemical studies, potentially for threat reduction, for contaminant tracing, and potentially to measure isotopically labeled compounds used in biological studies.